Elfdalian (considered a Swedish Sveamål dialect, but has official orthography and is, because of a lower degree of mutual intelligibility with Swedish, considered a separate language by many linguists, see p. 6 in this reference)

^From early Northern Middle English (Aitken, A. J. and McArthur, T. Eds. (1979) Languages of Scotland. Edinburgh,Chambers. p. 87). McClure (1991) gives Northumbrian Old English in The Cambridge History of the English Language Vol. 5. p. 23. In the Oxford Companion to the English Language (p. 894) the 'sources' of Scots are described as "the Old English of the Kingdom of Bernicia" and "the Scandinavian-influenced English of immigrants from Northern and Midland England in the 12-13c [...]." The historical stages 'Older—Middle—Modern Scots' are used, for example, in the "Concise Scots Dictionary" (Robinson M. (ed.) (1985) the "Concise Scots Dictionary, Chambers, Edinburgh. p. xiii) and "A Dictionary of the Older Scottish Tongue" (Dareau M., Pike l. and Watson, H (eds) (2002) "A Dictionary of the Older Scottish Tongue" Vol. XII, Oxford University Press. p. xxxiv).